1. Field of the Invention
The present invention relates to a method of deposition in which a workpiece for deposition such as a substrate made of resin is carried into a vacuum chamber or a deposition chamber and then a thin film is formed on a predetermined surface of the workpiece.
2. Description of the Related Art
Some deposition workpieces have a film thickness of the order of several μm. An automobile headlamp is one example of such a deposition workpiece. The headlamp is made by a deposition device or a vapor deposition device. The deposition device may be applied to manufacturing of a magnetic disk, manufacturing of a metallic film of a recording surface of a CD/DVD, manufacturing of a transparent electrode of a liquid crystal display or manufacturing of a photocatalytic film. When making the above-described product having a thin film, a substrate is formed by injection molding, masking or the like is performed of unnecessary portions of the substrate, and the substrate is then set in an exclusive deposition chamber. Next, the thin film is formed by a deposition element as described below. In addition, the same kind of deposition device is also used to deposit a protective film, which protects an organic emission layer on a substrate.
The above-described method of evaporation or the method of deposition forming a thin film on a surface of a substrate is known in the related art. For example, there have been known a sputtering method in which a surface of a substrate, which is a workpiece for the deposition, and a target material are placed facing each other, a negative voltage of several kV is applied to the target material in an argon gas atmosphere of several Pa to several tens of Pa, and thereby the thin film is formed by discharging. There have also been known an electron beam deposition method in which an electron beam, which is generated from an electron gun in a vacuum chamber, is emitted to a target material, which is heated and evaporated and thereby deposited on the surface of the workpiece. Further, there have been known an ion plating method in which a negative voltage of several kV is applied to a substrate and the vacuum evaporation is performed on the substrate under argon gas at a pressure of several Pa. Still further, a plasma deposition method and the like have been known in the related art. In addition, a method of chemical evaporation has also been known. As the target material used in the above-described deposition methods, compound targets such as oxide, nitride, carbide and the like have been known. Further, a metallic target, a powder target and the like have also been known.
JP-A-2008-221575 discloses a deposition device, in which an inner surface of a semi-hollow body of a pair of semi-hollow bodies, in other words, a surface of a workpiece for deposition, which is molded by a fixed mold and a movable mold, is covered in a deposition chamber, where a target electrode, a substrate electrode and a deposition element such as a vacuum suction tube or the like are provided, in a state where the workpiece is left in the fixed mold, and thereby deposition on the surface of the workpiece is performed in the fixed mold. JP-A-11-80927 discloses a deposition device, in which a main portion of a deposition chamber is covered by a earth shield material which also serves a mask.
According to the deposition device disclosed in JP-A-2008-221575, the deposition can be performed in the metallic mold using a deposition chamber without the workpiece being removed from the metallic mold. Therefore, the deposition surface is not contaminated with dirt from hands, dust or the like, so that a product having a high quality thin film of a favorable deposition state can be obtained. In addition, deposition is performed with the workpiece remaining in the metallic mold, so that inventory control of the semi-hollow bodies is not necessary. Furthermore, automatic molding can be performed with low price only by preparing the deposition device without using a specific mold.
However, the inventor has found points that are necessary to be improved. For example, a time when the workpiece is molded in the mold and a time when the deposition chamber is used and the deposition is performed, are not concurrent, so that waiting time occurs in order to match these timings, and efficient production may not be achieved. In addition, since an opening of the deposition chamber is in close contact with a parting surface of the mold, and a vacuum chamber is formed inside thereof, there is also a problem of sealing. In other words, since vacuum degree has influence on the quality of the product, a high sealing property is required. However, since an opening of the deposition chamber and a parting surface of the mold have different members from each other according to their purpose and have different configurations, sealing becomes a problem. Furthermore, in order for insertion and removal from the large deposition chamber between the molds which covers the concave portion of the mold, an amount of a mold opening of the molds becomes large, and a robot for inserting and removing the deposition chamber to and from the molds also becomes large.
For the above-described reasons, it is preferable that the workpiece for deposition, which is molded by the mold, is removed from the mold and is carried into the exclusive deposition device, and then the deposition is performed on the workpiece. Such a method is preferable when the workpiece is a planar shape and a portion to be deposited is a planar surface, because the portion to be deposited onto can face a target material only by carrying the workpiece into the deposition chamber and placing the workpiece in the deposition chamber. The above-described method of depositing the planar surface is disclosed in JP-A-11-80927.
However, a target material is sputtered by high energy particles such as plasma particles, and becomes target particles which have a tendency to fly straight. Accordingly, target particles are difficult to be attached to the deposition surface which does not face the target material. In other words, the target particles are difficult to be attached to a concave portion and a convex portion which are concealed with respect to the target material. When the deposition surface is configured of a plurality of different surfaces, the target particles may not be evenly attached. Thus, it is necessary that the deposition surface be held exactly by a jig or the like in order to carry the workpiece into the deposition chamber and portions which become concealed, decrease, or the deposition surfaces of different directions are facing the target material as much as possible. Thus, there are problems that time is further required to the deposition operation and the cost thereof increases.